Maybe it's time to move ZCN to the substitute opposite (i know, blasphemous
) If she wants she definitely has purpose on the team, but she can't just coast and needs to dedicate 100% (the same goes for anyone else)
At least in this match, I don't think Yao Di is the one that set Zhu Ting and Yuan XInyue too low (that's the usual problem, since most hitters in China are quite a bit shorter than them) but rather it's Ding Xia who's set a few low balls. Maybe her muscles still think she's in Liaoning?
Zhu Ting has a much younger sister, Zhu Jiahui. She plays setter on her school's team, but it sounds like she only plays volleyball for fun and to stay healthy. ZT said she'd also have liked to play setter except she's like 2m tall so yeah 
You can learn a lot about ZT from how she treats her sister. Jiahui was 11 back in 2017 when ZT brought her to the WGP finals. I think ZT "spoils" her lol, she goes to a private school (no prizes for guessing who pays for that) and ZT previously expressed the opinion that children should not experience shortage of money. Granted she also got a free apartment as part of some endorsement contract which she gave to her parents, in addition to another house that she paid for so it's not like her younger sister is the sole beneficiary.